The brief weakening of the trade winds over the Pacific Ocean earlier in August produced little warming of tropical sea surface temperatures. However, waters below the surface of the Pacific have warmed during the past few weeks, and therefore above-average temperatures near the surface are likely to persist or strengthen over the coming months.

Four of the seven climate models surveyed by the Bureau suggest El Niño is likely by the Australian summer of 2014–15. These model outlooks and current observations mean the Bureau’s ENSO Tracker remains at WATCH status. This indicates the chance of El Niño developing in the coming months is at least 50%, which is around double the normal likelihood of an event.

El Niño-like weather patterns can occur even if an event hasn’t become fully established. In 2014, these have included below-average rainfall across parts of eastern Australia, above-average daytime temperatures and a number of significant frost events.

The Indian Ocean Dipole (IOD) remains negative. Model outlooks suggest this negative IOD event is unlikely to persist for long, with models suggesting the IOD will return to neutral in early spring. A negative IOD pattern typically brings wetter winter and spring conditions to inland and southern Australia.